U.S. patent number 5,916,336 [Application Number 09/071,649] was granted by the patent office on 1999-06-29 for method and apparatus for cleaning absorbent materials.
Invention is credited to Richard G Middleton.
United States Patent |
5,916,336 |
Middleton |
June 29, 1999 |
Method and apparatus for cleaning absorbent materials
Abstract
A method and system for removing a lubricant from an absorbent
material. The method comprises placing the lubricant-contaminated
material in a dry cleaner and centrifuging the material to remove
and subsequently recover a first quantity of lubricant, dry
cleaning the material, separating and recovering a second quantity
of lubricant from the dry cleaning fluid, and recycling the dry
cleaning fluid. The present invention maximizes the recovery of
lubricant and effectively recycles the dry cleaning fluid, which in
turn minimizes both the cost and environmental impact of cleaning
absorbent materials.
Inventors: |
Middleton; Richard G (Columbia,
SC) |
Family
ID: |
24789605 |
Appl.
No.: |
09/071,649 |
Filed: |
May 1, 1998 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
694619 |
Aug 13, 1996 |
|
|
|
|
Current U.S.
Class: |
8/159; 68/18C;
68/18R |
Current CPC
Class: |
B08B
7/00 (20130101); B01D 41/02 (20130101); B09B
3/0058 (20130101) |
Current International
Class: |
B08B
7/00 (20060101); B09B 3/00 (20060101); B01D
41/02 (20060101); B01D 41/00 (20060101); D06B
009/00 () |
Field of
Search: |
;68/12.02,18C,18R
;8/142,158,159 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
WO 91/07537 68/12/02, May 1991..
|
Primary Examiner: Stinson; Frankie L.
Attorney, Agent or Firm: Mann; Michael A Nexsen Pruet Jacobs
& Pollard LLP
Parent Case Text
This application is a continuation of Ser. No. 08/694,619 filed
Aug. 13, 1996.
Claims
What is claimed is:
1. A method for removing lubricant from a material, said method
comprising the steps of:
determining whether a lubricant is petroleum-based or not petroleum
based;
centrifuging said material to separate a quantity of said lubricant
and impurities from said material;
if said lubricant is petroleum-based lubricant, forwarding said
separated lubricant and impurities to a tank having means for
removing petroleum-based lubricant from said impurities;
allowing said petroleum-based lubricant to separate from said
impurities in said tank, said petroleum-based lubricant rising to
the top of said tank as it separates;
dry cleaning said material;
distilling said dry cleaning solution to separate said drycleaning
solution from said lubricant;
if said lubricant separated by distilling is petroleum-based,
forwarding said petroleum-based lubricant from said dry cleaning
machine to said tank; and
skimming petroleum-based lubricant from said tank.
2. The method as recited in claim 1, wherein said centrifuging is
done at a speed of at least 450 RPM.
3. The method as recited in claim 2, wherein said dry cleaning step
is done using a solution of perchloroethylene.
4. The method as recited in claim 2, further comprising the step of
filtering said petroleum-based lubricant through a 200 micron
filter as it is skimmed from said tank.
5. The method as recited in claim 2, wherein said distilling step
takes place using an industrial distiller capable of distilling at
approximately 265.degree. F.
6. The method as recited in claim 4, wherein said dry cleaning step
is done in a dry cleaning machine adapted to pass effluent
containing dry cleaning solution and lubricants.
7. The method as recited in claim 4, further comprising the step of
filtering said petroleum-based lubricant through a 200 micron
filter as it is skimmed from said tank.
8. The method as recited in claim 1, wherein said dry cleaning step
is done in a solution of perchloroethylene.
9. The method as recited in claim 1, wherein said dry cleaning step
is done in a dry cleaning machine adapted to pass effluent
containing dry cleaning solution and lubricants.
10. The method as recited in claim 9, wherein said drycleaning
machine is a commercial dry cleaning machine without a filter and a
distiller.
11. The method as recited in claim 1, further comprising the step
of filtering said petroleum-based lubricant through a 200 micron
filter as it is skimmed from said tank.
12. The method as recited in claim 1, further comprising the step
of forwarding non-petroleum-based lubricants following centrifuging
to a storage container.
13. The method as recited in claim 1, wherein said distilling step
takes place using an industrial distiller capable of distilling at
approximately 265.degree. F.
14. A method for removing lubricant from a material, said method
comprising the steps of:
centrifuging said material to separate a quantity of a lubricant
and impurities from said material;
forwarding said separated lubricant and impurities to a tank having
means for removing said lubricant from said impurities;
dry cleaning said material;
distilling said dry cleaning solution to separate said drycleaning
solution from said lubricant;
forwarding said lubricant from said dry cleaning machine to said
tank;
allowing said lubricant to rise to the top of said tank as said
impurities settle to the bottom of said tank;
skimming lubricant from said tank; and
filtering said skimmed lubricant through a filter.
15. The method as recited in claim 14, wherein said centrifuging is
done at a speed sufficient to remove at least 98% of said lubricant
from said material.
16. The method as recited in claim 15, wherein said distilling is
done in an industrial distiller capable of distilling at a
temperature of approximately 265.degree. F.
17. The method as recited in claim 15, wherein said dry cleaning is
done in a commerical dry cleaning machine having no effluent
filter.
18. The method as recited in claim 14, wherein said distilling is
done in an industrial distiller capable of distilling at a
temperature of approximately 265.degree. F.
19. The method as recited in claim 14, wherein said dry cleaning is
done in a commercial dry cleaning machine having no effluent
filter.
20. The method as recited in claim 16, wherein said filter is a 200
micron filter.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for
removing oil from oil-absorbent pads or socks so that they can be
reused and the oil can be recycled without producing any hazardous
waste.
2. Discussion of Background
The desorption of oil and other industrial lubricants from
absorbent materials such as pads or "socks" is a prevalent
industrial process. As a result, the current art contains a variety
of different methods by which oil is removed from a material. What
follows is a brief overview of the art's current state.
U.S. Pat. No. 5,298,079 issued to Guymon sets forth a method
wherein oil filters are crushed while being simultaneously washed
with a surfactant. The crushed oil filters are then reprocessed
into steel.
U.S. Pat. No. 5,192,455, issued to Marcel, Jr. and U.S. Pat. No.
5,250,197, issued to Marcel, both disclose a system for removal
which includes subjecting the oil-containing material to squeeze
rollers, a solvent shower, and a centrifuge. Thereafter the
material is dried to restore it to a reusable condition.
U.S. Pat. No. 5,244,566 issued to Bond, teaches a special emulsion
of citric oil-in-water that causes the waste oil to separate into
three layers: an oil layer, an emulsion layer and a waste
layer.
U.S. Pat. No. 4,314,856 issued to Steimel sets forth a process
where an object is degreased, washed and dried in one location.
This is accomplished by tilting the axis of rotation of a
centrifuge and by operating the centrifuge at different speeds.
U.S. Pat. No. 3,566,892 issued to Logue teaches a device for use in
cleaning oil filters. The device contains means by which
various-sized filters may be cleansed.
However, there remains a need for an oil removal process that is
simple, effective and that allows the recovery of the oil as well
as the restoration of the material to a usable state.
SUMMARY OF THE INVENTION
According to its major aspects and briefly stated, the present
invention is a method and system for removing oil and other
lubricants from absorbent materials so that the materials can be
reused to absorb oils and the recovered oil can be recycled. The
system comprises a closed loop dry cleaning machine connected to an
industrial distiller, a source of dry cleaning fluid, a separation
tank for receiving petroleum-based lubricants, and a container for
receiving waste lubricants that are not petroleum-based. The
absorbent materials are loaded into the dry cleaning machine where
they are first centrifuged to remove excess lubricants. If the
lubricants are non-petroleum based, they are directed to the
container specifically designated for those types of lubricants. If
they are petroleum-based, they are directed to the tank. A valve
system controls the direction of flow, and each stream is pumped
through a filter that removes particulates before the waste
lubricants reach their respective containers.
The materials are then dry cleaned using perchloroethylene, as
usual, except that the dry cleaning machine has no filter or
distiller. Instead, the dirty perchloroethylene is routed to the
industrial distiller where it is distilled separately. The
distilled perchloroethylene is then returned to the dry cleaning
machine for reuse. The oil separated by the industrial distiller is
pumped through a filter to the separation tank.
At the separation tank, when the lubricant level rises above an
outlet, the recovered lubricants flow by gravity through a bag
filter to remove suspended particulates and on to a final oil
storage tank where the cleaned oil will be sold to approved oil
refineries.
A major feature of the present invention is the use of a dry
cleaning apparatus to centrifugally remove a quantity of
lubricants. Using a dry cleaner to centrifuge the absorbent
materials eliminates the need for a separate centrifuge device,
which in turn reduces machinery, as well as operational costs.
Another advantage gained by using a dry cleaner to centrifuge the
material is that the absorbent materials do not have to be moved
from the dry cleaning machine until the conclusion of the cleaning
process. They are put into the dry cleaning machine dirty and
removed clean. This reduces both labor and transportation
costs.
The use of the filters in combination with both the distiller and
separation tank is another very important feature of the present
invention. Because of this combination, the present process
produces no hazardous waste. Additionally, the dry cleaning fluid
is completely recycled, thereby reducing the cost of operations.
Moreover, the recovered oil is substantially free of both
particulate matter and fluids, which in turn increases its economic
value.
The use of an industrial distiller rather than a typical dry
cleaning machine distiller is another important feature of the
present invention. Because both the internal temperature and
pressure can be precisely controlled, the independent distiller
allows a more effective separation of the perchloroethylene from
the lubricants. This is turn maximizes the purity of the recycled
perchloroethylene and increases the recovery of lubricants.
Other features and advantages of the present invention will be
apparent to those skilled in the art from a careful reading of the
Detailed Description of a Preferred Embodiment presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings,
FIG. 1 is a flow chart of a method for removing a lubricant from a
material according to a preferred embodiment of the present
invention; and
FIG. 2 is a perspective view of a system for removing a lubricant
from a material according to the method of FIG. 1, with the fluids
within the interior of the separation tank illustrated in ghost and
a partial cutaway of a filter container.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2, there is shown a flow chart of a
method for removing a lubricant from an absorbent material
according to a preferred embodiment of the present invention and a
system for accomplishing the method described in FIG. 1,
respectively. It is recognized that although the method and system
of the present invention is described as removing a lubricant from
an absorbent material, the present invention may be utilized to
remove any fluid from an absorbent material. The first step in this
process is to determine whether the material to be cleaned is
contaminated with petroleum-based lubricants or non-petroleum-based
lubricants. This determination is routinely made by an artisan with
ordinary skill in the art without having to engage in undue
experimentation.
The contaminated material is then loaded into a dry cleaner 200.
Dry cleaner 200 may be any industrial size dry cleaner capable of
rotating at a speed between approximately 450 and 800 revolutions
per minute. Depending upon the dry cleaner used, it may be
necessary to replace the internal motor with another motor having
greater horsepower, so that a speed of between 450 and 800
revolutions per minute can be achieved. In addition, prior to
initiating the process as described in detail below, it is first
necessary to remove both the dry cleaner's internal filter and
distiller. This removal procedure, as well as the replacement of
the internal motor, is accomplished by the manufacturer of the dry
cleaning apparatus. An example of an industrial dry cleaner capable
of use with the present invention is a Victory-E series dry
cleaning system, manufactured by Victory Dry Cleaning Systems of
East Point, Ga.
Once loaded, the material is centrifuged until approximately
between 98% and 99.5% of the lubricant has been extracted from the
material. The next process step depends upon the type of lubricant
being removed. If the lubricant is petroleum-based, valve 210 is
opened and the oil lubricant stream exits dry cleaner 200 via
piping 220 and is forwarded to tank 230. The purpose of tank 230 is
to allow an operator to remove, via aperture 232, samples of the
fluid contained therein for analysis. Tank 230 is equipped with a
pump 240 having a filter 250 attached thereto. As pump 240 draws
oil from tank 230, filter 250 removes particles from the oil
stream. Upon leaving filter 250, the oil stream exits piping 220
and is received by a separation tank 270.
While residing in separation tank 270, gravitational forces affect
the separation of any liquid or solid contaminants, such as water
271 or dirt 275, still suspended within oil 276. These solid and
liquid contaminants settle to the bottom of tank 270, while the oil
rises to the top of tank 270.
Separation tank 270 is equipped with a pipe 280, located within the
upper region of tank 270 and in fluid communication with its
interior. When oil 276 within tank 270 reaches a certain level, it
enters pipe 280 and flows, by gravity, into a container 290 having
a filter 300 located therein. Preferably, filter 300 is sized to
capture solids having a particle size greater than or equal to
approximately 200 microns. Subsequent to filtration by filter 300,
the oil exits container 290 via piping 310 and is forwarded by
gravity into oil storage tank 320, where it is recovered and awaits
further processing. Once the oil has been removed from separation
tank 270, a valve 272 positioned in the bottom region of separation
tank 270 is opened to allow the water to drain therefrom. Solid
matter may be removed from the bottom of tank 270 through an access
door 274.
After the material residing within dry cleaner 200 has been
centrifuged, valve 210 is closed and a charge of dry cleaning fluid
is introduced to the interior of dry cleaner 200. The dry cleaning
fluid normally utilized in cleaning contaminated industrial
material is perchloroethylene (hereinafter "PCE"). Although the
present process is described using PCE, it is recognized that any
dry cleaning fluid normally employed in the art may be used without
departing from the spirit and scope of the present invention.
Once the charge of PCE has been added to dry cleaner 200, the
material is dry cleaned in accordance with normal industry
procedure. Afterwards, the material is removed from dry cleaner 200
and the interior of dry cleaner 200 is wiped with a cloth to remove
any residual PCE or oil. A valve 330 is then opened, allowing a
mixture of oil and PCE to flow through piping 340 and into
distiller 350. Distiller 350 may be any industrial distiller or
boiler commonly employed in the art capable of separating a
lubricant from a dry cleaning fluid. When dry cleaning a
petroleum-based lubricant using PCE, distiller 350 must be able to
achieve a temperature of approximately 265.degree. F. to affect the
phase separation. It is understood that the temperature at which
separation occurs will vary as a function of both the dry cleaning
fluid used and the type of lubricant removed, and therefore an
artisan with ordinary skill would alter the temperature of
distiller 350 accordingly. An example of a distiller capable of use
with the present invention is sold under the trademark SIVA.
Once distillation is complete, valve 354 is opened and the purified
PCE exits distiller 350 and is recycled via piping 352 into dry
cleaner 200. Such purified PCE may be used again to dry clean
contaminated materials.
The separated oil exits distiller 350 via piping 360 and enters
tank 370. Tank 370 is equipped with a pump 380 having a filter 390
attached thereto. The purpose of tank 370 is to allow an operator
to remove, via aperture 372, samples of the fluid contained therein
for analysis. As pump 380 draws oil from tank 370, filter 390
removes particulate matter from the oil stream. Upon leaving filter
390, the oil stream exits via piping 360 and is received by a
separation tank 270. Once received by separation tank 270, the oil
is processed in the same manner as detailed above.
In the alternative, if the lubricants to be removed are
non-petroleum based, then the pads are centrifuged within dry
cleaner 200 as detailed above. After centrifuging, valve 400 is
opened and the contaminants collected during centrifuge are
forwarded via pipe 410 into a drum 420. Valve 400 is then closed
while a suitable dry cleaning fluid is introduced to the interior
of dry cleaner 200. The pads are then dry cleaned and subsequently
removed from dry cleaner 200. Valve 330 is then opened to forward a
mixture of lubricant and dry cleaning fluid into distiller 350. The
fluid is then distilled to separate the dry cleaning fluid from the
lubricant. Once distilled, the lubricant travels through pipe 356
into a storage container 358 while the distilled dry cleaning fluid
is reintroduced to dry cleaner 200.
It will be apparent to those skilled in the art that many changes
and substitutions can be made to the preferred embodiment herein
described without departing from the spirit and scope of the
present invention as defined by the appended claims.
* * * * *